/Engine/Plugins/Experimental/Mutable/Source/CustomizableObject/Classes/MuCO/CustomizableObjectSystem.h
In case IsTextureParameterValueUnreal returns false, this will be used to query the texture data that must be copied in the preallocated buffer. The pixel format is assumed to be 4-channel RGBA, uint8_t per channel.
virtual void GetTextureParameterValueData ( const [FName](API\Runtime\Core\UObject\FName) & ID, uint8 * OutData )